A novel root-specific Di19 transcription factor from Glycine max compromises drought tolerance in Arabidopsis thaliana through suppression of auxin-related pathway

Di19 is a small family of transcription factors with two atypical Cys2/His2 (C2H2) zinc-finger like domains, which are involved in the regulation of stress responses, growth and development. To date, their potential roles as transcription factors is yet to be unraveled. In the present study, 15 Di19 members were identified in soybean, which were further named as from GmDi19–1 to GmDi19–15. In silica analysis provided a comprehensive understanding of their chromosomal location, exon number, cis-elements, phylogeny, and conserved motifs. GmDi19s had different tissue-specific expression patterns and most GmDi19s responded to at least one stress or hormone treatment, suggesting they have diversified biological functions during stress signaling. GmDi19–15, encoding a novel transcription factor that has not been identified and characterized in soybean genome, was specifically expressed in roots and GmDi19–15 fused with GFP was mainly located in the nucleus. In addition, GmDi19–15 showed transactivation activity in yeast cells, hinting its potential role as a bona fide transcription regulator. Ectopic expression of GmDi19–15 in Arabidopsis resulted in compromised drought tolerance. Transcriptomic data revealed that a consortium of mis-regulated genes was involved in the auxin-related pathway. Our results expanded the GmDi19 family with 8 new members identified. Moreover, the potential biological role of GmDi19–15 has been pinpointed using the model plant. The present study proposed GmDi19–15 could be a target for tissue-specific genetic modification as well as for generating high-performance traits under stress.